There has been known a system in which users can have voice chats with one another in a virtual space. This system is used in combination with, for example, a network game, so as to make the game more interesting. Conventionally, in order to make the voice chat in the virtual space more realistic, there has been a system as disclosed in Patent Document 1 below, in which voice data is distributed after the mixing has been completed, the mixing including sound image localization processing corresponding to a positional relation between speakers in the virtual space.
[Patent Document 1] Japanese Patent Application Laid-open No. 2000-244487